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The sequential nature of action ensures that an individual can anticipate the conclusion of an observed action via the use of semantic rules. The semantic processing of language and action has been linked to the N400 component of the event-related potential (ERP). The authors developed an ERP paradigm in which infants and adults observed simple sequences of actions. In one condition the conclusion of the sequence was anticipated, whereas in the other condition the conclusion was not anticipated. Adults and infants at 9 months and 7 months were assessed via the same neural mechanisms-the N400 component and analysis of the theta frequency. Results indicated that adults and infants at 9 months produced N400-like responses when anticipating action conclusions. The infants at 7 months displayed no N400 component. Analysis of the theta frequency provided support for the relation between the N400 and semantic processing. This study suggests that infants at 9 months anticipate goals and use similar cognitive mechanisms to adults in this task. In addition, this result suggests that language processing may derive from understanding action in early development.

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One of the key transitions in early cognitive development is from participating in face-to-face interactions to engaging in joint attention exchanges. It is known that the ability to jointly attend with another person to an object is essential for the development of abilities such as language in later life. Strikingly, little is known about the function of joint attention in infants in the first year. We developed a novel interactive-live paradigm to assess the neural mechanisms of joint attention in 9-month-old infants. An adult interacted with each infant, and infants' electrical brain activity was measured in two contexts. In the joint attention context, a live adult gazed at the infants' face and then to a computer displayed novel object. In the non-joint attention context the adult gazed only to the novel object. We found that the negative component of the infant event-related potential (ERP), a neural correlate indexing attentional processes, was enhanced in amplitude during the processing of objects when infants were engaged in a joint attention interaction compared to a non-joint attention interaction. These results suggest that infants benefit from joint attention interactions by focusing their limited attentional resources to specific aspects of the surrounding environment.

Abstract Many group-living animals, humans included, occasionally synchronize their behavior with that of conspecifics. Social psychology and neuroscience have attempted to explain this phenomenon. Here we sought to integrate results around three themes: the stimuli, the mechanisms and the benefits of interactional synchrony. As regards stimuli, we asked what characteristics, apart from temporal regularity, prompt synchronization and found that stimulus modality and complexity are important. The high temporal resolution of the auditory system and the relevance of socio-emotional information endow auditory, multimodal, emotional and somewhat variable and adaptive sequences with particular synchronizing power. Looking at the mechanisms revealed that traditional perspectives emphasizing beat-based representations of others’ signals conflict with more recent work investigating the perception of temporal regularity. Timing processes supported by striato-cortical loops represent any kind of repetitive interval sequence fairly automatically. Additionally, socio-emotional processes supported by posterior superior temporal cortex help endow such sequences with value motivating the extent of synchronizing. Synchronizing benefits arise from an increased predictability of incoming signals and include many positive outcomes ranging from basic information processing at the individual level to the bonding of dyads and larger groups.

Researchers from different backgrounds have an increasing interest in investigating infant cognitive development using electroencephalogram (EEG) recordings. Although EEG measurements are suitable for infants, the method poses several challenges including setting up an infant-friendly, but interference-free lab environment and designing age-appropriate stimuli and paradigms. Certain specifics of infant EEG data have to be considered when deriving event-related potentials (ERPs) to investigate cognitive processes in the developing brain. The present article summarizes the practical aspects of conducting ERP research with infants and describes how researchers typically deal with the specific challenges entailed in this work.

Combined with emotional expressions, eye gaze can provide essential information to indicate threat in the environment. The current study assessed the effects of eye gaze direction on infants' neural processing of fearful and angry faces. Event-related potentials were recorded from thirteen 7-month-old infants. Two face-sensitive posterior components, the N290 and P400, as well as a frontocentral negative component (Nc), indicating attentional arousal, were sensitive to eye gaze direction and emotion. A larger Nc was observed for angry faces with direct compared to averted eye gaze. Fearful faces elicited a larger N290 than angry faces, whereas angry faces elicited a more prominent P400 regardless of eye gaze direction. The findings are discussed in terms of early social cognitive and neural development.

Recent research has demonstrated that infants' attention towards novel objects is affected by an adult's emotional expression and eye gaze toward the object. The current event-related potential (ERP) study investigated how infants at 3, 6, and 9 months of age process fearful compared to neutral faces looking toward objects or averting gaze away from objects. Furthermore, we examined how the processing of novel objects is affected by gaze direction and emotional expression. We hypothesized that an adult's fearful expression should be particularly salient when it is directed toward a referent in the environment. Furthermore, responses to objects should be increased if the face previously expressed fear toward the object. Three-month-olds did not show differential neural responses to fearful vs. neutral faces regardless of gaze direction. Six-month-olds showed an enhanced negative central (Nc) component for fearful relative to neutral faces looking toward objects, but not when eye gaze was averted away from the objects. Furthermore, 6-month-olds showed an enhanced Nc for objects that had been gaze-cued by a fearful compared to a neutral face. Nine-month-olds showed an enhanced Nc for fearful relative to neutral faces in both eye gaze conditions and showed an enhanced Nc for objects that had been gaze-cued by a neutral face. The findings are discussed in the context of social cognitive and brain development.